title: Potentials of proniosomes for improving the oral bioavailability of poorly water-soluble drugs.
abstract: Abstract Objective: The objectives of this study were, first, to develop a free-flowing and stable proniosome formulation for poorly water-soluble drugs such as vinpocetine; and second, to estimate its bioavailability as oral drug delivery system.
  
  
  METHODS
  The proniosomes consisting of span60, cholesterol, sorbitol and vinpocetine were prepared by a novel approach. After the proniosomes were contacted with water, the suspension of vinpocetine-loaded niosomes formed automatically. The proniosomes and reconstituted niosomes were evaluated for their physicochemical characteristics, in vitro drug dissolution and release, integrity and stability at different GI tract pH conditions, in situ single-pass intestinal perfusion and in vivo bioavailability.
  
  
  RESULTS
  The proniosome powder exhibited excellent flowability. The reconstituted niosomes with high drug entrapment efficiency (89.67 ± 3.28%) showed spherical morphology with smooth surface under transmission electron microscope (TEM). X-ray diffraction (XRD) indicated that the drug was in an amorphous or molecular state in proniosome powder. In vitro dissolution and release study, proniosomes did enhance the dissolution and release rate compared to vinpocetine suspension in phosphate buffer solution (pH 7.2). Proniosome-derived niosomes could keep their integrity and stability at different GI tract pH conditions. The in situ single-pass intestinal perfusion indicated that encapsulation of vinpocetine into niosomes could largely improved the absorption of vinpocetine. The AUC(0-∞) of F2 and F3 was about 4.0- and 4.9-fold higher than that of the vinpocetine suspension, respectively. The results demonstrated the proniosomes indeed remarkably enhanced the oral bioavailability of vinpocetine.
  
  
  CONCLUSIONS
  This study suggested the potential of proniosomes as stable precursors for the immediate preparation of niosome carrier systems.
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University , Shenyang , China and.
authors.forename: Shuangshuang
authors.initials: S
authors.lastname: Song
authors.forename: Baocheng
authors.initials: B
authors.lastname: Tian
authors.forename: Fen
authors.initials: F
authors.lastname: Chen
authors.forename: Wenji
authors.initials: W
authors.lastname: Zhang
authors.forename: Yusheng
authors.initials: Y
authors.lastname: Pan
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
authors.forename: Xinggang
authors.initials: X
authors.lastname: Yang
authors.forename: Weisan
authors.initials: W
authors.lastname: Pan
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001682:Biological Availability; D007408:Intestinal Absorption / Q000187:drug effects / Q000502:physiology; D008081:Liposomes / Q000008:administration & dosage* / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D004364:Pharmaceutical Preparations / Q000008:administration & dosage / Q000737:chemistry / Q000378:metabolism; D011355:Prodrugs / Q000008:administration & dosage* / Q000737:chemistry / Q000378:metabolism*; D011817:Rabbits; D017207:Rats, Sprague-Dawley; D012995:Solubility; D014867:Water / Q000737:chemistry / Q000378:metabolism*
chemical_list: D008081:Liposomes; D004364:Pharmaceutical Preparations; D011355:Prodrugs; D014867:Water
keywords: Oral bioavailability; poorly water-soluble drugs; proniosomes; reconstituted/proniosome-derived niosomes; vinpocetine